Portable communication devices such as cellular telephones, personal computer (PC) cards, and wireless personal digital assistants (PDAs), typically include batteries for providing power to the circuitry of the device. The time that a device can operate before the charge of a battery is depleted depends on several factors including the power level and durations of wireless transmissions. The wireless transmitter and other circuitry used for the transmission of wireless signals consume relatively large amounts of energy compared to other circuits. Portable communication devices are required to operate in accordance with a radio configuration in order to communicate within a wireless communication network. For example, portable communication devices that operate in accordance with Code Division Multiple Access (CDMA) standards such as the IS-95 and IS-2000 CDMA standards must transmit signals in accordance with a Radio Configuration utilized by the particular communication network and base station. The term Radio Configuration is introduced in the IS-2000 standard which is revision of the earlier IS-95 standard. In the legacy IS-95 networks, radio configurations RC1 and RC2 may be used for both the forward link and the reverse link. For IS-2000 CDMA standards, new radio configurations including RC3, RC4, and RC5 were added to RC1 and RC2. In addition to the RC1 and RC2 radio configurations, IS-2000 compliant devices may use radio configurations RC3, RC4 or RC5 for the forward link and RC3 and RC4 for the reverse link. Accordingly, the IS-2000 CDMA standards must also support the legacy radio configurations RC1 and RC2 for backwards compatibility. Typically, the network uses the same radio configurations for forward link and reverse link with the exception that RC5 in the forward link usually maps to RC4 in the reverse link. Since the power consumption of the portable communication device is most affected during the transmission of wireless signals, the radio configurations of interest are the reverse-link radio configurations RC1, RC2, RC3 and RC4. A radio configuration is a set of forward traffic channel and reverse traffic channel transmission formats that are characterized by physical layer parameters such as data rates, modulation characteristics, and spreading rates. The different radio configurations impact power consumption and network capacity differently. For example, RC1 and RC2 use more network resources than RC3 and RC4. Power consumption by a portable communication device using RC1 or RC2 is less than power consumption by the same device using RC3 or RC4. RC3 and RC4 provide for more efficient forward power control than RC1 and RC2 resulting in an increased network capacity as compared to networks using RC1 and RC2. RC3 and RC4, however, typically require the transmitter to be active continuously whenever a call is active regardless of whether any voice or data packets are required to be sent on the reverse link while a device transmitter operating in accordance with RC1 and RC2 is turned on and off depending on whether voice or data packets are sent over the reverse link. The average transmission power for a device transmitting using RC1 or RC2 may be the same for a similar transmission using the corresponding SO using RC3 or RC4. The power consumption of the device, however, is significantly less for RC1 and RC2 than for RC3 and RC4 for similar data rates. Talk times for devices operating with RC3 and RC4 are typically 15% to 30% less than devices operating with RC1 and RC2.
Therefore, there is a need for power management of a portable communication device based on radio configuration.